A field effect transistor (FET) is a type of transistor that can use an electric field to control the shape and conductivity of a channel between a source and a drain. A Fin Field Effect Transistor (FinFET) is a type of FET where a silicon fin wraps around the conducting channel. A gate wraps around the fin, which provides better control over the channel and can reduce leakage from the channel. The dimensions of the gate determine the channel length of the device. Further, because the gate has better control over the channel than other types of transistors, turning off the gate results in lower leakage when the gate is off.
When a FinFET is created using a bulk silicon process flow, the top of the fin forms an active region, and the body of the fin extends below the active region into a well, creating a sub-fin leakage path. Current techniques to reduce leakage in this leakage path introduce dopant in the channel region, which is undesirable.
Features and advantages of the present disclosure will become more apparent from the detailed description set forth below when taken in conjunction with the drawings, in which like reference characters identify corresponding elements throughout. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the corresponding reference number.